Just one prisoner at Maghaberry handed illegal drugs over to prison authorities during a recent two-day drugs amnesty.
The amnesty was put in place at the high-security prison in order to “take drugs out of circulation” and “protect life”, the Northern Ireland Prison Service said.
However, just one prisoner made use of the amnesty and handed over what Justice Minister Claire Sugden described as “a small amount of suspected cannabis”.
Ms Sugden had been asked for a figure detailing the number of prisoners to make use of the amnesty by DUP MLA Lord Morrow.
Responding to another query from DUP MLA Sydney Anderson, the minister outlined the measures taken to “prevent drug dealing in prisons”.
She said: “The supply of illegal substances is a significant problem faced by society in general and the criminal justice system throughout Northern Ireland is not immune from its effects. A range of measures are in place to prevent illicit drugs coming into prison, these include the use of passive drugs dogs, visitor and staff searches. NIPS continue to work closely with police colleagues to identify individuals involved in the supply of illicit substances.
“Recently the Prison Service has placed increased emphasis on intelligence-led searching and the evidence is that this approach is targeting the right people and that drugs are being detected.”
A Northern Ireland Prison Service spokesperson said: “Anyone who takes illicit substances puts themselves at risk of serious harm. Governors will use all tools at their disposal to keep prisoners safe.
“In extraordinary circumstances that can include an amnesty to protect life and take drugs out of circulation.”